JPH08253272A - Package - Google Patents

Abstract

PURPOSE: To provide a package which can be surely unsealed automatically at a low internal pressure due to heating by a microwave oven. CONSTITUTION: In a sealed package comprising a tape-like interlayer easy-to-peel material 4 interposed in a heat-sealed part 2 to be opened, an outermost layer of the material 4 having a heat-sealed layer 52 of a package body 1 and heat- sealed layers 41, 42 which can be heat-fused respectively, and an inner layer having an easy-to-peel layer 43, wherein the material 4 protrudes inward with respect to the heat-sealed part 2 of the package body, one or more cuts are provided inside the package body in a direction perpendicular to the material 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food package which has a high hermeticity and is easy to open automatically in a microwave oven.

[0002]

2. Description of the Related Art Conventionally, in order to heat a packaged food which has been sealed by heat sealing in a microwave oven, the bag is once opened with scissors to destroy the hermeticity of the bag and heated in a microwave oven. This is because otherwise the bag is ruptured by the steam vaporized by heating and the contents are scattered.

In order to solve such a problem, it has been proposed by the present inventors to interpose a tape-shaped easily peelable material between layers at the heat-sealing portion to be opened. According to this method, automatic opening can be surely performed with a microwave oven, but the internal pressure at the time of opening is relatively high at about 1 kg / cm ^2, and the heat-sealing layer of the package body needs to be structured to withstand this.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cheaper package by ensuring automatic opening with a low internal pressure.

[0005]

In order to solve the above problems, the present invention has a tape-shaped inter-layer easily peelable material interposed at least in a heat-sealing portion to be opened, and the tape-shaped inter-layer easily peelable material has a package as an outermost layer. It has a heat-sealing layer of the main body and a heat-sealing layer capable of heat-sealing, respectively, and has an easily peelable layer as an inner layer, and is provided so as to project to the inside of the package body more than the heat-sealing portion of the package body In the hermetically sealed package, one or more cuts are provided in the tape-shaped easily peelable material inside the package body in a direction perpendicular to the tape-shaped easily peelable material.

[0006]

[Function] Since the tape-shaped inter-layer easily peelable material is provided with one or more cuts in the direction perpendicular to the tape-shaped inter-layer easily peelable material inside the package body, when the internal pressure is applied, the cut part easily serves as the starting point. It can be opened automatically.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a front view of the bag main body 1, in which a heat seal portion 2 hermetically stores the contents 3. In the portion A, the heat-sealing portion 2 is formed by the heat-sealing layer (described later) of the tape-shaped easily peelable material 4 and the heat-sealing layer of the bag body, which are notched in the perpendicular direction.

FIG. 2 is a vertical sectional view of the heat-sealing portion shown in FIG.
As shown in the figure, the tape-shaped easily peelable material 4 is inserted between the laminates 5 of the bag body by heat fusion.

FIG. 3 is an enlarged front view of the heat-sealing portion A in the opening. As shown in the figure, the tape-shaped inter-layer easily peelable material 4
There is a notch 45 in its length, and its length reaches the inside of the heat sealing part. The number of cuts 45 is not particularly limited as long as it is one or more, but the larger the number, the more stable the opening can be performed at a low pressure. Therefore, it may be appropriately selected depending on the size and content of the opening. The cut 45 need not be a straight line, but may be a curved line or a slanted line, and may have any shape as long as it reaches at least the lower end edge of the heat-sealing portion.

FIG. 4 shows a typical structure of the tape-shaped inter-layer easily peelable material 4. Layers 41 and 42 for heat-bonding to the laminated body 5 of the bag body are laminated by the easily-peelable adhesive layer 43. ing. The base materials 411 and 421 of the layers 41 and 42 include
Polyester, nylon (trade name), polypropylene,
Polyethylene or the like is suitable, and either a simple substance or a composite thereof may be used. In addition, heat bonding layers 412 and 422
As the resin, a resin that can be heat-bonded to the heat-bonding layer of the bag body, for example, polyolefin such as polyethylene or polypropylene, ethylene-vinyl acetate copolymer, polyester or polyamide is used. If the base materials 411 and 421 have thermal adhesiveness to the laminated body 5 of the bag body, the thermal adhesive layer 41
2, 422 can be omitted. In addition, the base material 41
A printing layer, a coloring layer, or the like can be provided between the first and second layers 421 and the adhesive layers 412 and 422.

The easily peelable adhesive layer 43 is composed of a resin layer 431 and an adhesive layer 432, and the resin layer 431 has a relatively weak adhesive strength, such as vinyl resin, urethane resin, acrylic resin, polyamide resin, silicone resin, or the like. It is composed of a single substance or a mixture and is formed by a part coat of this resin. An example of the pattern is shown in FIG.
As shown in (b) and (c), the uncoated portion forms a pattern such as a dot shape, a line shape, or a grid shape.

As the adhesive layer 432, a known two-component curing type urethane dry laminating adhesive is usually used, but it may be a pressure sensitive adhesive. In the case of an adhesive, the resin layer 4
31 may be omitted.

FIG. 6 shows the structure of the laminated body 5 of the bag body in FIG. 2, which is composed of a laminated body of a base material 51 and a heat sealing layer 52, and is made of a conductive material such as aluminum foil in the laminated body. Must not contain body. The base material 51 is a laminate of a surface protective layer 511, a gas barrier layer 512, and a reinforcing layer 513, and a printing layer and a coloring layer can be appropriately provided.

The present invention is not limited to this depending on the application, and for example, there may be a structure without the gas barrier layer 512 or a structure without the reinforcing layer 513. Further, the positions of layers 512 and 513 may be interchanged. As the heat-sealing layer 52, polyolefin, ethylene-vinyl acetate copolymer resin, etc. are used, but the heat-sealing layer 52 is not limited to this, and the heat-sealing layers 52 are heat-sealed to each other, and the tape-shaped interlayer easily peelable material 4 is used. It suffices that it can be heat-sealed with the heat-bonding layers 412 and 422.

Next, the principle of improving the automatic opening property in the microwave oven by making the notch 45 in the tape-shaped easily peelable material 4 will be described.

FIG. 7 shows a state where internal pressure is applied to the heat sealing portion 2 of FIG. In FIG. 7, since the tape-shaped easily peelable material 4 is provided so as to project inside the bag body,
When pressure is applied to the bag body, the force to open the bag acts on the point a, so the force to peel the tape-shaped interlayer easily peelable material 4 is applied to the thickness (t) of the bag body, and the tape-shaped interlayer easily peelable material. When the tensile adhesive strength (Pa) of 4 is exceeded, it is opened.

FIG. 8 is a sectional view of the bag in which the tape-shaped easily peelable material 4 does not protrude inside the bag body. FIG. 9 shows a state when internal pressure is applied to FIG. As shown in FIG. 8, when there is no protrusion of the tape-shaped interlayer easily peelable material 4 to the inside of the bag body, the force to open the bag body when the internal pressure is applied to the end portion b of the easily peelable layer 43. To work,
When the peeling strength (Pb) of the tape-shaped easily peelable interlayer material 4 is exceeded, it is opened. Although it is affected by the rigidity of the tape-shaped easily peelable material 4, it is clear that Pa >> Pb in the region of the soft packaging material. If a bag as shown in FIG. You can However, in actual production, if the tape insertion position shifts even a little, the laminated body 5 of the bag body 5
Since it covers the tape-shaped easy-to-peel material 4, it is impossible to stably manufacture such a bag.

On the other hand, as shown in FIG. 3, when the notch 45 is formed in the tape-shaped easily peelable material 4, the state shown in FIG. 8 is locally created, and the tape can be opened at a low pressure.

FIG. 10 is a plan view of a planned opening portion in a state where the bag main body shown in FIG. 1 is filled with contents and internal pressure is applied. When the internal pressure is actually applied, the heat-sealing portion 2 is always deformed to generate a wavy portion as shown in the figure. If the notches 45 correspond to the deformed portions c, d, and e (the notches 45 are formed, the deformed portions are likely to be deformed conversely), the unsealing is not successful. this is,
This is because when the notches 45 correspond to the deformed portions c, d, and e, unlike in FIG. 7, the angle of the tape-shaped easily peelable material 4 changes and the opening pressure changes, as shown in FIG. 11.

Pw is the force acting to open the bag by the internal pressure, and Pw is the force acting to peel the tape-shaped interlayer easily peelable material, and θ is the angle of the tape-shaped interlayer easily peelable material. Since it is a component force of P, the following formula is established.

P = Pw / cos θ ∴ θ = 45 degrees P = 1.4 Pw θ = 70 degrees P = 2.94 Pw That is, in the case of FIG. 11, at an angle of 45 degrees compared with the case of FIG. A force (internal pressure) of about 1.4 times and about 3 times at 75 degrees is required.

Especially in the case of a flat bag, it rarely expands uniformly,
Inevitably, the heat-sealing part is deformed and a part as shown in FIG. 10 occurs. If the notch 45 corresponds to this deformed portion or its vicinity (it is easy to deform because the notch 45 is made), it is difficult to open it. Therefore, make notches at 2 or more places, preferably 3 to 6 places. If the notch 45 corresponds to the position of the state, it is possible to stably open at a low pressure.

If the opening is small, cut 4
Since the number of 5 is naturally limited, the number may be selected according to the shape and size of the bag.

On the other hand, since the shape of the bag is stable even when expanded, such as a self-standing bag, there is no such deformation.
One cut is sufficient.

Regarding the width of protrusion of the tape-like easily peelable material 4 into the body of the package, a notch 45 is made to locally form a region of substantially 0 mm and the region is opened. There is no. Therefore, the protrusion width may be determined in consideration of cost and manufacturing variations.

Depending on the contents, there are various ones such as those which are desired to be automatically opened at a considerably high pressure and those which are desired to be automatically opened at a low pressure, but by adjusting the adhesive strength of the easily peelable layer 43 of the tape-shaped interlayer easily peelable material 4, A stable automatic opening pressure in the microwave can be set.

Although the above embodiments have been described focusing on the packaging bag and the self-supporting bag, the present invention can be applied to a flexible bottle obtained by the blow molding method as well as the bag. Also in this case, heat sealing may be performed by interposing the tape-shaped inter-layer easily peelable material having the above-mentioned cut at the planned opening portion.

12 and 13 show another embodiment of the tape-shaped easily peelable interlayer material 4. FIG. 12 shows an easily peelable material formed by coextrusion of a synthetic resin, and at least one of the interlayer adhesive force between layers 41 and 43, the interlayer adhesive force between layers 42 and 43, or the cohesive force between layers 43 is used. Choose the resin so that it is weaker.

In FIG. 13, the layers 41, 42, and 43 are simply laminated by a thermal bonding method to form the tape-shaped easily peelable material 4. As in the case of FIG. 12, the resin is selected so that at least one of the interlayer adhesive force between the layers 41 and 43, the interlayer adhesive force between the layers 42 and 43, or the cohesive force of the layer 43 is weakened.

Further, the layers 41 and 43 or the layers 42 and 43 are laminated by an adhesive method using an adhesive or a co-extrusion method, and then laminated by the thermal adhesive method with the layer 42 or the layer 41. It doesn't matter. Furthermore, the materials 41, 42, and 43 are separately prepared without producing the easily peelable material 4 in advance,
It is also possible to insert and heat bond during bag making.

Incidentally, in FIG.
Is inserted over the entire length of the upper portion of the bag body 1, but it may be partially inserted.

Next, an experimental example of a package which is easy to open automatically in the microwave oven of the present invention will be described.

Experimental Example 1 A flat bag as shown in FIG. 1 was produced. The tape-like easily peelable material 4 (see FIG. 4) is composed of a polyester film having a thickness of 25 μm for the layers 411 and 421, an unstretched polypropylene film having a thickness of 60 μm for the layers 412 and 422, and an acrylic resin for the layer 431. Part coat was applied in the pattern of FIG.

For the layer 432, a commercially available two-component curing type urethane dry laminate adhesive was used. The structure of the laminated body 5 of the bag body (see FIG. 6) is that the layer 51 is a polyester film having a thickness of 12 μ and the layer 52 is an unstretched polypropylene film having a thickness of 60 μ, and is a commercially available two-component curing type urethane dry laminate adhesive. Bonding was performed with the agent.

The number of cuts in the tape-like easily peelable material 4 was set at 0, 1, 2, 4, and 6 to make the tape protrusion width to the inside of the bag body was 3 mm, and 6 bags each were prepared. 150 g each of white rice was filled and sealed. Each was heated with a commercially available microwave oven with an output of 800 W and the opening state was observed. The results are as shown in Fig. 14. All the bags were automatically opened at the planned opening site, but there was scattering of the white rice outside the bag when the number of cuts was 0, but when the number of cuts was 1, 2, 4, 6 the white rice was scattered. There was little or no.

The remaining three bags were sealed without being filled with anything, and a burst strength test was conducted. The results are as shown in Fig. 15. As the number of cuts increased, the product stably ruptured from the site to be opened under low pressure.

Experimental Example 2 A flat bag as shown in FIG. 1 was produced. The structure of the tape-shaped easily peelable material 4 (see FIG. 4) is that the layers 411 and 421 are 12 μm thick polyester film, the layers 412 and 422 are 40 μm linear low-density polyethylene film (LLDPE), and the layer 431. Was coated with acrylic resin in the pattern shown in FIG.

For the layer 432, a commercially available two-component curing type urethane dry laminate adhesive was used. The structure of the laminated body 5 of the bag body (see FIG. 6) is that the layer 51 is a polyester film having a thickness of 12 μ, and the layer 52 is a linear low-density polyethylene film (LLDPE) having a thickness of 60 μ. Bonding was performed with a urethane type dry laminate adhesive.

The number of cuts in the tape-shaped inter-layer easily peelable material 4 is 0, 1, 2, 4, 6 to make the tape protrusion width to the inside of the bag body is 2 mm, and 6 bags each are prepared. Then, 150 g of white rice was filled and sealed. Each was heated with a commercially available microwave oven with an output of 800 W and the opening state was observed. The results are shown in FIG. 14, and all the bags were automatically opened at the planned opening site. However, when the number of breaks was 0, the white rice was scattered outside the bag, but when the number of breaks was 1, 2, 4, and 6, the white rice was scattered little or not at all.

The remaining three bags were sealed without being filled with anything, and a burst strength test was conducted. The results are as shown in Fig. 15. As the number of cuts increased, the product stably ruptured from the site to be opened under low pressure.

Experimental Example 3 A flat bag as shown in FIG. 1 was produced. The structure of the tape-shaped easily peelable material 4 was the same as in Experimental Example 2.

The structure of the laminated body 5 of the bag body (see FIG. 6) is
Layer 51 is a 12 μ thick polyester film, layer 52
Is a linear low-density polyethylene film (LLDPE) having a thickness of 40 μm, and the two-component curing type urethane dry laminate adhesive which is commercially available was used for bonding.

The number of cuts in the tape-shaped inter-layer easily peelable material 4 was set at 0, 1, 2, 4, and 6 to make the protrusion width of the tape into the inside of the bag body 2 mm, and 3 bags each were prepared. Each was filled and sealed. 800 for each commercial output
It was heated in a W microwave oven for home use and the opening condition was observed.
The result is shown in Fig. 14, and the number of cuts is 2 out of 3 bags.
The bag was not opened from the planned opening site but was opened at the heat-sealing part (side seal part) between the bag bodies. All the rest were automatically opened at the planned opening site, but there was a slight scattering outside the bag of white rice at the number of cuts 1 and 2, but there was no scattering of white rice at 4 and 6, which was good.

From the above [Experimental Example 2] and [Experimental Example 3],
If you do not make a cut, the microwave will not open automatically in the microwave unless the thickness of the linear low-density polyethylene film (LLDPE) in the bag body is 60μ or more, but if you make a cut, even if it is 40μ, it will automatically open in the microwave. It turns out that cheaper packaging materials can be selected.

[0046]

EFFECTS OF THE INVENTION The packaging of the present invention, which is easy to open automatically in a microwave oven, has a notched tape-like easy-to-peel material inserted into the heat-sealing portion of the body of the packaging by heat fusion. Since it is opened from the starting point, it is possible to perform automatic opening in a microwave oven with very stable low pressure and without failure.

Further, since it is possible to open the package body at a constant pressure, a cheaper material can be selected as the material of the package body, which is highly advantageous in terms of cost.

[Brief description of drawings]

FIG. 1 is a front view of a bag showing an embodiment of the present invention.

FIG. 2 is a partially enlarged vertical sectional view of a heat-sealing portion of the bag shown in FIG.

FIG. 3 is a partially enlarged front view of a partially enlarged heat-sealing part.

FIG. 4 is an enlarged cross-sectional view of the tape-shaped easy-to-peel material.

FIG. 5 is a plan view showing a coating pattern of the above-mentioned easily peelable adhesive layer.

FIG. 6 is an enlarged cross-sectional view of the laminated body of the bag body.

FIG. 7 is a partially enlarged cross-sectional view when internal pressure is applied to the bag body of FIG.

FIG. 8 is a partially enlarged cross-sectional view of a bag in which the tape-like easily peelable material does not protrude inside the bag body.

FIG. 9 is a partially enlarged sectional view when internal pressure is applied to the bag body of the above.

10 is a plan view of a planned opening portion in a state where internal pressure is applied to the bag body of FIG.

FIG. 11 is a relational diagram of stress and its component force at the deformed portion (d, e) of the bag body of FIG.

FIG. 12 is an enlarged cross-sectional view showing another embodiment of the tape-shaped easily peelable material.

FIG. 13 is an enlarged sectional view showing still another embodiment of the above.

FIG. 14 is a table showing the results of automatic opening in microwave ovens of Experimental Examples 1, 2, and 3.

FIG. 15 is a table showing the burst strength test results of Experimental Examples 1 and 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packaging bag 2 Heat-sealing part 3 Contents 4 Tape-shaped interlayer easy peeling material 41, 42 Heat-sealing layer 43 Easy peeling layer 45 Notch into tape-shaped interlayer easy peeling material 5 Laminate of bag body 51 Base material 52 Heat-sealing layer a Point of action of pressure on the tape-like easily peelable material b Point of action of pressure on the easily peelable adhesive layer c, d, e Deformation part of seal when internal pressure is applied

Claims (5)

[Claims] 1. A tape-shaped inter-layer easily peelable material is interposed at least in a heat-sealing portion to be opened, and the tape-shaped inter-layer easily peelable material has a heat-sealable heat-sealing layer at the outermost layer. In a hermetically sealed package having a fusing layer and an easily peelable layer as an inner layer, wherein the easily peelable material is provided so as to project to the inside of the package body rather than the heat-sealing portion of the package body, in the form of a tape. A packaging body, characterized in that one or more cuts are provided in the packaging body in a direction perpendicular to the tape-like easily peeling material. 2. The package according to claim 1, wherein the easily peelable layer comprises an adhesive layer and a part-coated resin layer having a lower adhesive strength than the adhesive layer. 3. The package according to claim 1, wherein the tape-shaped easy-release layer material is formed by coextrusion of a synthetic resin. 4. The package according to claim 1, wherein the tape-shaped easy-release layer material is formed by thermal bonding. 5. The package according to claim 1, wherein the easily peelable layer is an adhesive layer.